Transmission control



Aug. 14, 1934- P. 1 .TENNEY r:r AL

' TRANSMISSION CONTROL .2 Sheets-Sheet Original Filed May 51. 1929 Ali@14, 1934- P. L. TENNEY ET AL Re.l 19,275

IRANSMISSION COJJ'ROI'.;

original Filed 'May s1. 1929 2 sheets-sheet 2 Reissued Aug. 14, 193419,215 TRANSMISSION coN'rnor.

PerryLTennemLansinmdHarryEFl-dler,

Detroit, Mich., assignors to General Motors Corporation, Detroit, Mich.ware s corporation of Dela- Orlglnal No. 1,783,931, dated December 2,1939,

Serial Nn. 367,243, May 31, 1929.

for reissue December 645,446

Application 2, 1932. Serial No.

44 Claims. (Cl. 'I4- 3365) automatically operating mechanism, itselfsubject to manual control, to operate the change speed mechanism inaccordance with the engine speed and with driving eilort or motortorque. Another object is to arrange for having the driving ratiobetween the driving and driven shafts change automatically, the changesbeing made b y variations in engine speed and by changing pressureconditions in the engine manifold or by movements of the throttle valve.Other objects and advantages will be understood from the followingdescription and the accompanying drawings. In the drawings, Figure 1 isa.view in side elevation of an engine of a motor vehicle with the clutchhousing and transmission housing' associated therewith, the transmissioncontrol device being shown in longitudinal section.

Figure 2 is a top plan view, partly broken away, of the change speedmechanism, the iluid pres- -I sure operating means being shown inSection, this being an embodiment of the invention designed for directmanual control.

Figure 3 is a sideelevation of the embodiment of the invention shown inFigure 2, the cover plate for the fluid pressure operating means beingremoved and parts being shown in section. Figure4isasectiononline4-4ofFigure3. Figure 5 is a view in side elevation of a modificationof the structure shown in Figure 1.

Referring rst to Figures 2 3-4, numeral 7 represents a transmissionhousing associated with the clutch housing 8, located, as usual, at therear of the engine 10, the latter not shown in Figure 2, but representedin Figure 1. The transmission mechanism within housing 7, is designed toa'ord variable speedsbetween the driving shaft 9, and the driven shaft11. The transmission is not per Se a partof this invention. It comprisesa ball member 13, carried by driving shaft 9, and a yoke 15. having acircular series of rollers, gripping theball. A lever 19 is movablymounted to eil'ecta predetermined angular relation between shafts 9 and11, whereby a reduction in driving ratio is effected toan extentproportional to the said angularity. When shafts 9 and 11 are inalignment, the drive is in direct,

or high, speed. Low speed is effected by the maximum angularity betweensaid shafts.

This invention is primarily concerned with the mechanism for rotatinglever 19 to change the angularity between shafts 19 and 11. As shown inFigure 2, lever 19 is connected byrod 2l with lever arm 23 on shaft 25,these parts being better shown in Figure 4. Shaft 25 is journalled at 27in the casing. Shaft 25 has a second arm 29. To the end of arm 29 isconnected the end of a oating lever 31. Intermediate its length, lever3l is pivotally connected at 33 to the end of a lever arm 35, on a shaft37. Shaft 37 has an operating arm 39, preferably outside the casingcover 41. 'I'he upper end of lever 31 is connected by a link 43 to avalve stem 45, Valve stem 45 carries valves 47 and 49, controllingpassages 51 and 53, respectively, said passages 51 and 53 aiiordingcommunication from a passage 55 to the cylinder 57 on one side or theother of the piston 59, which is movable in' cylinder 57. A pipe 63leads to passage 55 from any suitable source of iluid supply, such as apump or reservoir,l not shown. Piston 59 is connected by its rod 61 tothe lower` end of lever 31 and arm 29. In Figure 3 we have shown insection the instrument board 64 on which is mounted a lever 65. From thelever 65 extends a link 67, the link being connected at its lower end tothe end of arm 39. When the parts are positioned as Shown in full linesin Figure 3,

. the driving and driven shafts of the transmission are assumed to be inalignment; The valves are closed. If the lever 65 is moved toward thedotted line position, arm 39 swings clockwise, as also does arm 35. Theresistance oiiered by the transmission elements and by the piston 59 inthe cylinder 57, renders the lower end of oating lever 31 relativelyimmovable, as compared with the upper end. The lever 31 therefore swingscounterclockwise about its lower end and pulls upon rod 43, and opensvalve 49. This opens up a passage for a iiow of iluid from passage '55through 53 into the right hand end of cylinder 57. The piston 59 istherefore moved to the right. Since its rod is connected to the lowerend of lever 31, to which lever arm 29 is also connected, this movementof the piston operates through arm 23 and rod 21 to swing lever 19andchange the driving ratio between' the driving shaft 9 and drivenshaft 11. The movement of the piston also operates as it turns lever 31about its pivot 33 to move link 43 to the rightand to clo valve 49. Afurther movement of the transmission may be eiiecte'd by a 'furthermovement of lever 65, the valve being self-closing after each movementofthe lever.

In Figure 1, lever 39" corresponds to lever 39 in that its rotationoperates the same transmission within housing 7 for controlling thespeed reduction. In this case the lever 39' is controlled onlyindirectly by a, manually operated lever. In this form, provision ismade to vary the angularity of the shafts 9 and l1l in accordance withthe oper- A ation of the engine. We have shown provision for varying thereduction ratio in proportion to the speed of the engine and also inproportion to the degree of suction in the engine manifold.

Lever 39', which may be called a movable means to control thetransmission, is connected by a link 65 to a rod 67 slidably guided in asleeve 69 in the end wall 71 of a housing 73 positioned adjacent theengine. Within the housing 73 the rod 67 is pivoted to an intermediatepoint of a movable member or bar 75 positioned normally at a right angleto rod 67. To offer resistance to the'movement of bar 75 to the left aresprings 77 connected to the member 75 at substantially equal distancefrom the pivot of the bar 75, whereby the action of the springs isequalized. At their other ends the springs are connected to a rock shaft79, journalled at 81 in the casing walls. Rotation of the rock shaft tovariably (and equally) tension springs 77 is effected by `a lever 83 atthe dash, a bell crank 85, and connecting links 87 and 89. Within thehousing 73 is rotatably mounted a shaft 91. Shaft 91 extends out througha suitable bearing 93 in the front wall of the housing and is jointed toa shaft 95 which is to be driven by the engine in any suitable way.Pivoted to a sleeve 97, rotatably carried by the shaft but held fromaxial movement thereon, are a pluralityof -links 99. Rotatably andslidably mounted on shaft 91 is a second sleeve 101 spaced from sleeve97. Sleeve' 101 has pivoted thereto a series of links 103. Links 103 and99, at their adjacent ends, are pivoted to each other, weights 105 beingcarried by pivotal connection. This construction is designed toconstitute a centrifugal governor. Lever 75 is extended beyond itsconnection with the upper spring 77, and at its end is connected to themovable sleeve 101, so that when said sleeve moves, as to the left,under the centrifugal 'action of weights 105', it moves the upper endout of lever 75 with it. At the bottom of case 73 is a cylinder 107within which is a piston 109. A rod 111 connects piston 109 to the endof lever 75. A tube 113 connects the engine manifold 115 with acyllnderv107, the suction of the manifold tending to move the piston 109to the left, the piston being subject to atmospheric pressure on theright. This movement wilL tend to move bar 75 to the left and throughits movement operate to cha e the transmission through theinstrumentality o links 65 and lever 39. It will be evident thatincrease in engine speed will causean increase in rate of rotation ofshaft 91. The centrifugal governor will therefore be effective to pullbar 75 to the left and operate through link 65 and arm 39' to change thespeed ratio lof the transmission. In such movement of bar 75 to theleft, under the influence of the governor or of suction of cylinder 107,the bar may be moved against the tensionof springs 77, which may bevariably controlled through the action of manually operated lever 83. Itwill be seen, therefore, that if the position of lever 39' is suchastomaintain the transmission in its low speed position a movement of 75to the left, due to the governor or to increase in suction cylinder 107,or both, will change the transmission ratio toward its normal or directspeed.

It will be understood that manual effort applied to lever 83 isloperable to tensionsprings 77 and tomove bar 75 toward the right, thisaction opposing the action of the automatic mechanism tending to movebar 75 to the left. The lever 83 therefore becomes a manually operablemechanism functioning to oppose a shift toward higher driving ratios.Through its manipulation it becomes possible to keep the speed ratiodown at a. time when the automatic Vmechanism might vtend to shift theratio up. The manipulation of the lever 83 therefore makes possiblebetter acceleration.

The normal position of lever 83 will be such that the rate of shiftingunder the influence of the automatic mechanism will be such as isdesired by the operator for ordinary driving conditions. In the eventthat additional acceleration be desired, it is only necessary to modifythe action of the automatic mechanism by manipulating the auxiliarymanual control.

In Figure 5, we have shown as a substitute for the suction operatedmechanism a mechanical connection between the throttle valve and the bar75. In this case the arm 115l on pivot axis 0f the throttle valve isconnected by a link 117 to a bell crank 119. The bell crank ispivoted105 at 120. A rod 121 is pivotally connected to the bell crank at 123.This rod 121 is connected to a rod 125, the latter to be pivotallyconnected to the bar 75 as shown in Figure 1. lFor proper guidance ofthis rod connection, rod 121 may 110 have an enlargement 127, guided ina suitable member 129. In this form of the invention, when the throttlevalve is open and the suction condition of the manifold is reduced, theconnections produce precisely the same effect as when the 115 piston 109is at the right hand end of cylinder 107, in Figure 1. Since a closedthrottle corresponds with high suction, the operation is substantiallythe same as in the form shown by Figure 1.

As shown in Figure 1 and Figure 3, the transmission housing 7 isextended somewhat to the rear of the parts already described. T hepurpose "of this extension is to provide for associating with thegearless variable speed transmission an in- 125 dependent transmission,to provide for reverse drive and, if desired, a further low speed ratio.Such second transmission unit is not a part of this invention and sinceit may be Aof any known form, it need not be described or illustrated. v

application. l

Having described the invention, we claim: Y

1. In combination with an in'nitely Variable transmission, an operatingmechanism therefor comprising. an operable Xmember, transmissionactuatingv means to actuate said variable speed transmission, a iiuidpressure valve, a connection between said operable member and said valveand said transmission actuating means whereby said operable memberoperates through said valve to move said transmission mechanism by fluidpressure and. whereby said connection thereafter closes said valve,together with a power cylinder having a pistonl said cylinder bein'g incommunication with said valve, said connection including a floatinglever, one end of said lever operably connected to said valve, the otherend -of said lever operably connected to said transmission operatingmeans and to the piston of the power cylinder.

2. In combination, a variable speed transmission comprising a drivingshaft and a driven shaft, driving means therebetween, means to vary theangular relation between said shafts to vary the drive ratiotherebetween, a iuid pressure control valve, a power cylinder with apiston therein, the cylinder being in communication with said valve, alever, one end of said lever operably connected to said valve, theotherend of said lever connected to said means for varying the angularity ofthe transmission shafts and also connected to said piston, an operatingmember, a mechanical connection therefrom to an intermediate point ofsaid lever.

3. In combination, an engine having an induction conduit, a variablespeed transmission comprising a driving shaft and a driven shaft,driving means therebetween, meansl to vary the angular relation betweensaid shafts to vary the drive ratio therebetween, mechanism movable bychanges in engine speed, and an operable connection between saidmechanism and the said means to vary the driving ratio.

4. In combination, an engine having an induction conduit, a variablespeed transmission comprising a driving shaft and a driven shaft,driving means therebetween, means to vary the anl gular relation betweensaid shafts to vary the driving ratio therebetween, mechanism movable bychanges in the fluid pressure within said induction conduit, and anoperable connection between said mechanism and the means to vary thedriving ratio.

5. In combination, an engine having an induction conduit, a variablespeed transmission, comprising a driving shaft and a driven shaft,driving means therebetween, means to vary the angular relation betweens'aid shaftsto thereby vary the driving ratio'therebetween, mechanismmoved by changes in engine speed and the changes in the pressure withinsaid conduit, and an operable connection between said mechanism and themeans for varying the driving ratios.

6. In combination, an engine having an induction conduit, a variablespeed transmission, movable transmission operating means, to change thespeed ratios provided by said transmission, mechanism movable by changesin engine speed and by changes in the pressure within said conduit tomove said movable means together with resilient means normally operableto produce a low speed driving ratio within said transmission.

7. In combination, an engine having an induction pipe, a variable speedtransmission to be driven by said engine, movable means to vary thespeed ratio of said transmission, a centrifugal governor and an enginesuction operated device, a movable member, said member being connectedto said movable means and to said governcr'and said suction controldevice, together with resilient means connected to and operating toresist such movements of said member as operate to increase the speedratio provided by -ber and the movable means and a mechanism saidtransmission, and manually operated means to control the tension of saidresilient means.

8. In combination with an internal combustion engine, having a fuelintake conduit, a shaft driven by said engine, a governor on said shaft,a uid pressure cylinder having a piston, a pipe from said fuel conduitto said cylinder, a lever member terminally connected to said governorand said piston, a variable speed transmission for said engine, movablemeans to vary the speed ratio thereof, a connection between said levermember and said means.

9. The invention defined by claim 8, together with resilient meansconnected to and operable upon said member against that motion of themember by the governor and piston which tends to increase the speedprovided by the transmission, and manually operable means to control theaction of said resilient means'.

l0. In combination, an internal combustion engine, having a fuel inletconduit, a variable speed transmission driven by said engine, fluidpressure operated means to vary the speed ratio of said transmission,said fluid pressure operated means including a power cylinder and aself- 100 closing valve, movable means to control said transmission, aconnection from said movable means to said valve, said connectionincluding a lever, a'connection from said lever to said power cylinderthrough which said power cylin- 105 der operates to close the valve, amovable member, a connection between said movable member and movablemeans, automatically operable mechanism controlled by the speed of theengine to move said movable member.

11. In combination, an internal combustion engine having a fuel inletconduit, a variable speed transmission driven by said engine, saidtransmission having a shifting device, fluid pressure operated means tovary the speed ratio of said transmission, said fluid pressure operatedmeans including a power cylinder having a piston and a'valve, said valvebeing in connection with said cylinder, movable means to control saidtransmission, a lever pivoted to said movable means, a. connection fromone arm of the lever to the valve, connections between the other arm ofthe lever and the piston of the power cylinder and also the saidshifting device, a movable member, a connection between the movablememresponsive to the speedv of the engine and the pressure within saidfuel inlet to automatically control the action of said transmissionthrough said movable member and movable means.

12. The invention defined by claim 11,' together with resilient means,connected to and operable upon said movable member to reduce the speedratio of said transmission, and manually operable means to control saidresilient means.

13. In combination with an internal combustion engine of a vehicle, avariable speed transmission comprising a driving shaft and a drivenshaft and driving means therebetween, means to vary the angular relationbetween said shafts to thereby vary the driving ratio therebetween,mechanism moved by variation in engine speed and connecting meansbetween said mechanism and the ratio varying means to automatically movesaid ratio varying means.

14. An engine having an innitely variable speed transmission connectedthereto, fluidpressure mechanism, connections betweenk said fluidpressure mechanism and said variable speed transmission whereby thefluid pressure mechanism operates to control the speed ratio of saidtransmission, a floating lever, connecting means between said floatinglever and said uid pres,- sure mechanism, a member movable in responseto changes in engine speed, and a connection between said member andsaid lever.

15. In combination, an engine having an induction conduit, a variablespeed transmission, movable transmission operating means, to change thespeed ratios provided by said transmission, mechanism movable to movesaid movable means, said mechanism being jointly and independentlyresponsive to engine speed and to pressure changes within said conduit,and manually operable means to move said mechanism,

16. In combination, an engine having an induction conduit, a variablespeed transmission, movable transmission operating means to change thespeed ratios provided by said transmission, mechanism movable by changein engine speed and by changes in the pressure within said coni duit tomove said movable means, resilient means speed responsive means forinfluencing the mo-` tion of said means, other means responsive to theposition of said throttle control member for inuencing the motion ofsaid speed ratio selecting means, said other means being operable bothjointly with and independently of said speed responsive means, andadditional means manually operable to influence the motion of said speedratio selecting means.

18. In power` transmission control mechanism,

an engine and a throttle therefor, a variable speed transmission, aspeed ratio selecting device therefor, means responsive to said throttleposition operable through a fluidcolumn for ini-luencing said speedratio selecting device, a speed responsive device for influencing saidspeed ratio selecting device, said throttle responsive means and saidspeed responsive device being jointly and independently operable, andauxiliary manual modifying means for moving said speed ratio selectingdevice.

19. In power transmission control mechanism, an engine, a variable speedtransmission, a speed ratio changing device including auxiliary poweroperating means, iluid operated means for influencing selection of speedratio, speed responsive means for influencing selection of ratio, saidfluid operated means and said speed responsive means being operablejointly and independently, movable means connecting said speed ratiochanging device with both of said last named means,

and .additional manually operable means for Amoving said last namedmeans.

said governor, auxiliary power means for actuatpendently operablemechanisms, and additional l means manually operable to move said'means.

22. In combination with an automatic speed ratio changing mechanism formotor vehicles, a movable control element including means responsive to.variations in speed of the motor, means responsive to variations inmotor torque, and means operative to vary the effect of both said meanson said movable control element for predetermined changesin speed andload.

23. In combination with an automatic speed ratio shifting mechanism formotor vehicles, a movable control element operative to actuate saidmechanism, .and means forv displacing said control element includingmeans responsive-to variations in motor torque, means responsive tovariations in speed of the motor, and means operated to simultaneouslyvary the effects transmitted by said last two named means to saidmovable control element for predetermined changes in load and in speed.f

24. In combination, a motor, a driving shaft, a driven shaft, ratiochanging transmission mechanism between said shafts, -a levercontrolling said transmission mechanism, means to actuate said lever,speed responsive means operable upon said lever-actuating means andmeans responsive to motor torque also operable upon said lever-actuatingmeans together with manually displaceable means to adjust saidlever-actuating means independently of said speed-responsive and motortorque responsive means.

25. An engine having a suction region, a driving shaft, a driven shaft,ratio-changing transmission between said shafts, means responsive to thespeed of the driving shaft and operable upon said ratio-changingmechanism, and means responsive to the degree of suction within saidsuction region'also operable .upon said ratio-changing mechanism.

26. In a power transmission mechanism, in combination, an engine havingan intake suction duct, a driving shaft, a driven shaft, a variablespeed transmission therebetween whereby their relative speeds may becontrolled, a movable control member for said transmission, a devicecontinuously responsive to the degree of suction in said intake duct andconnected to said control member whereby the motion of the latter ispro- 27. An engine having an intake suction duct, a

driving shaft, a driven shaft, coupling mechanism therebetween wherebythe driven shaft may be operated from the driving shaft at variablespeed ratios, a control for saidcoupling mechanism, a devicecontinuously responsive to the degree of y suction in said engine intakeduct and operably connected to the control for said couplingmechanismwhereby the speed` ratios between said driving and driven shafts maybevaried, and auxiliary control means operably connected to said controlfor said coupling mechanism to modify the effect of the deviceresponsive to degree of vacuum.

28. In power transmission control mechanism, in combination, an enginehaving a suction chamber, a variable speed transmission, a speed ratiochanging element, means responsive to variations in suction in saidsuction chamber for influencing selection of transmission speed ratio,speed responsive means for influencing selection of speed ratio, movablemeans connecting said speed ratio changing element with both of saidlast named means, and additional means operable upon the movable meansfor influencing selection of ratio.

29. In a power transmission device, an engine, a driving shaft, a drivenshaft, ratio changing mechanism therebetween, a transmission speed ratiocontrolling element, a speed responsive element, an element responsiveto motor torque, and means interconnecting these elements whereby thedriving ratio is determined jointly thereby, said means including afloating lever.

30. In a power transmission device including a prime mover, aspeed-controllingelement for .the prime mover, a transmission speedratio selecting element, a speed responsive element, and meansinterconnecting these elements whereby the driving ratio is determinedjointly by the will of the operator acting through the speed-controllingelement and by the operating conditions of the power transmissionoperable through the speed-responsive element, said means including afloating lever, the connections of the'speed-controlling element and thespeed-responsive element with the lever constituting fulcra each for theother. A

3l. In a power transmission mechanism, any

engine, a throttlefor the engine, a variable speed transmission, speedratio controlling means for the transmission, a speed-responsivegovernor mechanism, a differential motion mechanism, and meansconnecting said differential motion mechanism with said throttle, saidspeed ratio controlling means and said governor mechanism.

32` In a power transmission control mechanism, in combination, anengine, a throttle, a variable speed power transmission, a speed ratiochanger for the transmission, an auxiliary fluid pressure device foractuating the change of ratio in the transmission, a governor, movablemeans connected to said speed ratio changer, throttle, and governor, andseparate control means for influencing the motion of said last-namedmeans.

33. In combination, a motor including a driving shaft, a driven shaftadapted to be coupled in various speed ratios to said driving shaft, andmeans continuously operative -by changes in the suction exerted by themotor and by the speed of one of said shafts to change the relativespeeds of said'driving and driven shafts.

34. In combination, a motor including a driving shaft, a driven shaftadapted to be coupled in various speed ratios to said driving shaft,meansl continuously operative by variations in the suction of the motorto change the relative speeds of the driving and driven shafts, andmeans operative to modify the action of sai nist-named means. 'I

35. In combination, a motor including a driving shaft, a driven shaft,ratio-changing coupling mechanism between said driving and drivenshafts, a lever controlling said mechanism, means operative by changesin motorv torque and by variations in speed of one of said shafts toactua-te said lever, and additional means operable to modify said means.

36. In combination, an engine, a driving shaft, a driven shaft, a speedratio changing transmission between said shafts, a speed ratio controlelement therefor, differential motion mechanism operative to move saidspeed ratio control element, means responsive to the speed of one-ofsaid shafts to vary the movement of said diierential motion mechanism,and additional manual means operative to vary the degree of movementimposed by said speed-responsive means.

37. An engine, an operator-controlled engine throttle, a driving shaft,a driven shaft, a variable speed ratio coupling between the shafts,including a speed ratio actuating member, auxiliary power meanscontinuously operative to move said mem,- ber, a speed ratio selectorcontinuously operative to control said auxiliary power means, and adevice continuously movable by changes in the speed of one c-f theshafts and -byv variations in the motion of said operator-controlledengine throttle to position said speed ratio selector.

38. In an automatic speed control system for motor vehicles, incombination, a transmission speed ratio control element; speedresponsive means continuously operative to influence the motion of saidspeed ratio control element, means responsive to motor torquecontinuouslyy operative to influence the motion of said speed ratiocontrol element, and manual means to modify the rate of change of speedratio` for predetermined conditions of load and speed. l

39. In automatic controls for motor vehicles, in combination, an engine,a driving shaft, a driven shaft, a variable speed transmission betweenfthe shafts, an automatic control device therefor, including a governorresponsive to the speed of one of the shafts, operator-controlled meansconnected to said device and constantly operative to influence selectionof speed ratio, said means coincidentally controlling said engine speed,and additional operator-controlled means operative to vary the rate ofchange of transmission speed ratio for predetermined operatingconditions.

40. In automatic velocity control systems for motor vehicles, incombination, a transmission speed ratio control element,speed-responsive means continuously operative to influence the motion ofsaid element, torque-responsive means jointly and continuously operativeto iniiuence the motion of said element, operator-operative meansjointly and continuously effective to influence the motion of saidelement, and additional manual means to modify the rate of change vofspeed ratio for predetermined conditions of load and speed.

, 41. In automatic velocity control systems for motor vehicles, incombination, a transmission speed ratio control element continuouslyeffective to change transmission speed ratio, speed-responsive meanscontinuously operative to influence the motion of said element,torque-responsive means jointly andl continuously operative to influencethe motion of said element, operatoroperative means jointly andcontinuously effective to influence the motion of said element, andadditional manual means to modify the rate of change of speed ratio forpredetermined conditions of'load and' speed.

42. In automatic velocity `control systems for motor vehicles, incombination, a transmission yspeed ratio control element,speed-responsive means continuously operative to influence the motion ofsaid element, torque-responsive means iolhtly and continuously operativeto influence the motion of said element, operator-operative meansjointly and continuously eifective tov influence the motionl of saidelement, additional manual means to modify the rate of change of speedratio for predetermined conditions of load and speed,` and iiuidpressureratio actuatingr` means connected to said transmission speedratio`control element.

43. In automatic velocity control systems for motor vehicles, incombination, a transmission 'speed ratio control element continuouslyeffective to change transmission speed ratio, speedresponsive meanscontinuously operative to iniluence the motion of said element,torque-responsive means jointly and continuously operative to influencethe motion of said element, operator-operative means jointly andcontinuously effective to iniiuence the motion of said element,additional manual means to modify the rate of change of speed ratio forpredetermined conditions of load and speed, and duid pressure ratioactuating means connected to said Vtransmission y

